In the art of silver halide photography it is well known to use compounds that image-wise release a photographic useful group such as e.g. a dye or dye precursor, a silver halide solvent, a fogging agent, an antifogging agent, a development inhibitor, a development accelerator, a developing agent, a chemical or spectral sensitizing agent, a toning agent etc. Some of these type of compounds are commonly employed to produce colour images (see for example Angew. Chem. Int. Ed. Engl. 22 pages 191-209, 1983) but are also useful in black and white materials to obtain a photographic material having a high speed, high contrast etc. For example U.S. Pat. No. 4,724,199 discloses compounds capable of releasing a fogging agent to obtain a photographic material of high speed and high contrast.
Some of these type of compounds may also be used to obtain a negative working silver salt diffusion transfer material. See for example U.S. Pat. No. 4,693,955 and the Japanese published unexamined patent application no. 15247/59. By the term "negative working" is meant that the exposed parts of the photographic material yield the image parts while the term "positive working" implies the formation of image parts corresponding to the non-exposed parts of the photographic material.